A cobpo



H R. CANFIELD.

METHOD AND MEANS FOR CONTROLLING ELECTRIC CIRCUITS.-

APPLICATION FILED MAN. 6, 1920.

Patented June 22, 1920.

4- SHEETSSHEET l.

Indeolor H. R. CANFIELD.

METHOD AND MEANS FOR CONTROLLING ELECTRIC CIRCUITS.

APPLICATION men mm. 6. mac.

1,344,260. PatentedJune22, 1920.

4 SHEETS-SHEET 2.

R' 0 IL 5a,

Witness Int/antar- H. R. CANFIELD.

METHOD AND MEANS FOR CONTROLLING ELECTRIC CIRCUITS.

APPLICATION FILED MAR. 6. 1920 1 44,260. Patented June 22, 1920.

4 SHEETS-SHEET 3.

salad/a0 2.1 1 1094172 Witness 1. or

H. R. CANFIELD. METHOD AND MEANS FOR CONTROLLING ELECTRIC CIRCUITS. APPLICATION men MAR. 6. I920.

1 44,260. Patented June 22, 1920.

4 SHEETS-SHEET 4.

UNITED STATES PATENT OFFICE. i

HARRY R. CANFIELD, OF CLEVELAND, OHIO, ASSIGNOR TO THE ELECTRIC CON- TROLLER & MANUFACTURING COMPANY, OF CLEVELAND, OHIO, A CORPO- BATION OF OHIO.

METHOD AND MEANS FOR CONTROLLING ELECTRIC CIRCUITS.

Specification of Letters Patent. Patented June 22, 1920.

Continuation of applications Serial No. 583,060. filed September 21, 1910, and Serial No. 604,331, filed January 24, 1911.

To all whom it mag concern:

Be it known that I, HARRY R. (JANFIELD. acitizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented new and useful Improvements in Methods and Means for Controlling Electric Circuits, of which the following is a specification.

My invention relates to electric controllers of that type in which the flow of current in one or more electric circuits is controlled by a series of magnetically-oper ated switches. More particularly it relates to controllers for starting motors and make use of the current traversing the controlled circuitfor controlling the operation of the several switches.

One object of my invention is to eliminate the shunt windings used in the operating coils of the usual type of magneticallyoperated switch together with the complicated control systems connected therewith.

Another object of my invention is to pro vide a self-contained switch which will refuse to close its contacts so long as the current flowin'g'through its actuating winding is too high,or above a predetermined value.

Another object is to provide a switch on which it is not necessary to use a magnetic blow-out with the details attendant thereto, and to provide a switch which is cheap to construct.

Referring to the accompanying drawings, Figure 1 is a side elevation of my switch, parts being in section; Fig. 2 an end elevation thereof; Fig. 3, a view s owing in elevation and section a second form of construction; Fig. 4, a view showing in side ele vation and vertical section a third form of construction; Fig. 5, an end elevation of Fig. 4; Fig. 6, a diagram of current values for operation of the switch at different adjustments; Fig. 7 a dia rammatic view showing the manner of wiring theswitch so that when the contacts are closed the actuating winding of the magnet will be in series with those contacts; Fig. 8, a wiring diagram of a motor starter; and Fig. 9 a wiring diagram of a. modified construction.

Referring first to Figs. 1 and 2, which show only one of the many forms. which my switch may assume, S is an open rectangu. lar frame of magnetic material, such as cast This application filed March 6, 1920.

Serial No. 363,868.

iron, mounted on an insulating base or support S At opposite sides of the frame S are the bosses or magnetic poles S and S, one of them (8) being the inner end of the plug 8" of magnetic material, such as cast iron, threaded in an opening in the frame so as to be adjustable for a purpose to be hereinafter stated.

Between the poles S and S is the body of the plunger or armature S composed of magnetic material and provided preferably with an extension S of preferably smaller cross-section than the said body.

The plug S is provided with an opening in which is the non-magnetic separator S. I find the ordinary soft stcela suitable material of which to construct the plunger or armature S with its extension S The plunger or armature S has connected thereto the non-magnetic rod S pivoted to the contact arm S, which is pivoted to the frame S at the bearing S The engagement of the shoulder S en the rod S with the top of the frame limits themovement of plunger S toward the pole S.

The annular winding S surrounds preferably the pole S and the plunger 3 at the place where its cross-section changes, which is at the junction of its extension S with the body. The body of the plunger S is shorter than the distance between the poles S and S so that it may have reciprocatory movement between the same under the influence of the winding S. r

The. gap Fl between the plunger S and the pole S, I will call the operating gap, and the gap S between the plunger body and the pole S, I will designate as the lock out gap. I have found that, by the construction hereinabove described or its equivalent. if the winding S is energized beyond a definite value, the weight of the plunger and the parts movably connected thereto together with the magnetic pull in the gap S, that is, between the plunger S and the pole S is greater than the pull in the opposite direction in the gap S, that is, between the plunger and the pole S, thereby causing the plunger to remain in its original position, as shown on Fig. 1. I have also found that when the excitation of the winding S is diminished to the said value, the magnetic pull on the plunger will predominate in the gap S", causing the plunger to move toward the pole S and the arm S to make contact with the brush S. After the switch has been closed as described, the gap S has been reduced so that the plunger S will hold the swi tph clo sed with a very small amount of excitation in the winding S. B screwing the plu 8 one way or the otlier and, consequent 'y, changing the relative sizes of the two gaps S and S, the point in tlie ezgcitatipn of the winding S at which the plunger operates to close the switch can varied between wide ranges. I do not limit myself to making the pole S only adjustable.

I have observed that inthe construction of the switch shown in Fig. 1 the magnetic flux appears tofiow in a divided path in a part of the magnetic circuit, when the winding S is energized. The magnetic flux maybe rearded as flowing from a point in-the frame, such as the pole S, across the gap S into the armature S. Here the flux divides into two, paths part flowing through a substantially continuous path including the exten- SlO S 3 andinto-the. lugs and the frame 8', lr-to the pole or the starting point, the other part flowing from the armature S across the gap S: into the pole S and thence throu h theplu S and the frame S to the ole The ux flpwin across the gap S prod cos a force! ten, ing to raise the plungery ihe fluxthrnugh the gap S" prolfie orc n ng-m. sw at he pl ger from being raised. f the winding is excited at ,a low value the Larger. part of the flux produced thereby will flow through the extension S39 and sintm it passes horizontally into the frame S, there is no tendency to prevent the plunger from moving upward, only a small part of the flux passing across the gapSi. If the winding is excited at a high value the-restricted area in the magmotile-circuit at thezextension S forces more flux to; pass into the pole S. across the gap S, thereby increasing the force tendin .to prevent the upward movement of the pfunget. I do not restrict myself to the precise constructi n shown for producing. parallel or divided paths for the magnetic flux, nor do I restrict myself to any definite location of the same, since the structure and location of the=parts may be changed without departing from the principles of my invention.

I do. not limit myself to. any theory of the operation o,f my switch. In its action it appears that when the. winding S is excited tee hi un m magn t n n, the r s s swata 'a t. c n S tha a t ap ut tha as eicitae n of the W ding diminishes, the magnet1c pull in the gap S! decreases faster than in the gap S", so that, when the excitation has decreased to a certain valuo, the pull in the. gap S" will e redoma aw I have found it desirable to make the opposing surfaces on the opposite sides of the gap 'of different areas. In Fig; "II have shown the area of the pole S larger than the upper face of the plunger S, and in Fig. 3 I have shown it smaller, as at S".

The terminals of the switch are shown at S and S", andthe terminals of the windin are shown at S and S Iieferring now to Figs .4 and Qughich bear the same reference characters as corre sponding parts in Figs. 1 and 2, except that small letters are used instead of capitals, the frame 8' is shown to be U-shaped and the winding 8 is held in place by the screws 8 The winding 8 is wound on the tube 8 which extends up to a point near the top of the frame and constitutes a dust-Shield.

The tubular separator a. is secured to the extension 8 so as to. travel therewith. .The rod 5 is made. preferably of non-magnetic material. The plug 5" is prevented from accidental movement by the jam-nut s. The operation of the apparatus shown in Figs. 4 and 5 is substantially the same as that described for Figs. 1 and 2 and will be readily understqod therefrom.

My invention is applicable both to direct and alternating current circuits, but in alt/ernating currentcircuits the operation of my apparatus depends on the ampere turns in the energizing windings, and not on the frequencies of alternation.

In Fi 6 I show two. curves X and Y, respective y, indicating the values of current in the winding S, at which the switch will operate, and at which it will lock 0 en at different adjustments of the air gap g". The ordinates of the curves represent am-, pores in the winding of a certain size wire and number of turns. The abscissae represent the length of the air gap S in inches.

The curve shows that the switch will operate on 8 amperes flowing in the winding any adjustment of the air gap from .2 The curve Y shows that if the air gap, S is, say .3, the value of current above which the switch will lock open is 25 amperes and that it will operate when the current lowers to a point below 25 ampercs. It is thus, seen that by varying the air gap. S" the value Of current at which the switch will loclg open will vary.

Referring to Fig. 7, it will be seen that the switch S is actuated by current flowing from the positive through the resistance R and the winding S of the switch to the negative, but that as soon as the'contacts. of the switch close, the current flows from the. positive through the switch contacts and the winding S to the negative, thereby shortcircuiting the resistance R and placing the switch contacts in series with the actuating winding S'.

Fig. 8 showsa wiring diagram for a motor llf) 40 the windings, as shown at K for the winding starter in which I have shown my switches employed to successively cut out sections of resistance from the motor circuit. The motor is shown with armature A and series field F. Upon closure ofthe switch S the motor circuit is established from the posi tive main P through the switch S, the winding 8', the sections R, R and R ofresistance, and the armature A and the field F of the'motor tothemegativemain N. If the current 'in this-circu it' just established is above .the 'limit -at which the switch 8 is set to operate, the switch S will "not close immediately, but will remain open until the motor speed increases, thus decreasing the current to the limit just mentioned. The switch S will then close, short-circuiting the -resistance section R, and establish a circuit including its-own winding 3' to-.

gether with the winding 8 of the switch S", the resistance sections R and R and the motor armature and field; This :will increase the current in the motor circuit, and if this current is above the limit at which 1 theiswitch: S J-isset to operate, the latter willwremain open until" the motochas again increased its speed and reduced the current to that limit. The switch 'S 'will thenclose, short-circuiting the "resistance Section R, and include the .winding s"*- of the switch s". in the motor. circuit. Likewise the-switchrS will remainiopenrnntil the motor current has again-decreased to the limit at which it is set to operate, when .it will close its contacts, short-circuiting the remaining section R of the resistance, and connect'the motor across the line with only the operatingwindings s, 8 ,and-s of the switches in series therewith.

By-connecting a shunt resistance around 8 of the switch S ythe windings may be made to take a part only of the motor current.

'The switches will noiv remainclosed until K1 the motor circuit is opened at. the switch S,

at which all the arc of breaking the circuit is tal en,1there being no are found at the contactsof the switches S, S", andSK In Fig. 9 I have shown a different arrangement of starting resistance, the sections R, RQxand It being connected inparallel and finallyshort-circuitedi ;-I have also shown.the main switch B in'the form of the ordinary magnetic switch, having a shunt winding 12, and controlled by the hand switch H. The motor has the armature A and the shunt field f. When the hand switch H is closed, the winding 6 is energized, causing the switch B immediately to close and a circuit to exist-through the field windin f. At the same time a circuit is establis ed from the main P through the switch B, the winding 8', the resistance section R, and the armature A to the negative main N. If

the armature current is not above a predetermined'value, or when it has diminished to that value, the switch S closes connectin the resistance section R in parallel with the section R, and including the winding 8 of the switch S in the branch containing the resistance section R". In a similar manner the switch S closes, connecting the resistance section B in parallel with the sections R and R", and including the winding of the switch 3' in the branch containing the section R. The armature current again diminishes and the switch S closes a circuit through its own winding, short-circuiting all of the resistance sections R, R and R, as well as the windings of the switches S and S". These switches, therefore, fall open. The motor'circuit through the armature is then from the main P through the contacts of t'heswitch B, the contacts of the switch 8% the winding of theswitch S and the motor armature A to the other main N. When the hand switch H is opened, .the switch B opens, taking all of the arc'of rupturing the circuit, whereupon the switch S opens If desirable each switch can be set to close when the motor current is at a different value so that any acceleration of the motor speed can be secured to suit any condition of load.

For simplicity I have shown my invention in connection only with-the eontrol'of nonreversing motors, but it is clear to those skilled in the art that the principle of my in- 00 vention may be applied as well to reversing motors or other dynamo electric machines, or to the control of any circuit over which passes a variable current to be controlled.

It is thus seen that I have provided a sys- 105 1cm of control by which several separately actuated switches may be made to automatically progress to cut out the resistance in a circuit, the progression of the switches being at all times under the control of the circuit 110 itself, all of which is accomplished without the use of shunt windings on the switches, auxiliary contacts, or relays. By the use of a simple winding of coarse conductor on each switch, three functions areperformed; 115 namely, the winding furnishes the magnetization for operating the switch; it produces a force delaying the operation until the excitation of the winding is at its proper value; and it holds the switch in its operated 120 position until a very small current passes through its contacts.

In one aspect of the case. the armature portions may be regarded as a part of the switch member.

This application is a continuation of my application Serial Number 583,000, filed September 21, 1910, and m application Serial Numher 604,331, filed anuary 24, 1911.

In some of the appended claims a struc- 130 ture is described in which flux may be set up by current in the controlled circuit however supplied to the structure, irrespective of the number of coils through which current passes. a

With respect to some of the appended claims, itiis immaterial what means may be employed to carry out the other functions of the structure, so long as the particular functions described in such claims are effected by flux set up by current in the controlled circuit. a i

I claim:

1. A controlling device for electric circuits comprising a switch member biased to open position, electromagnetic means ener gized by current in the circuit to produce two magnetic forces, one for moving the switch member to closed position, and the other for holding itin open position, said forces varyingat different rates as the current in said circuit varies.

.2. A controlling device or electric circuits oomprising a switch member biased to open position, electromagnetic means energized by current in the circuit which reinforces the bias sufficiently to prevent the switch from closing when the energizing current is relatively high but overcomes the bias when the energizing current is low,

3. A circuit to be controlled, a switch member normally biased -to open position controlling the circuit, and means controlled by the current in said circuit acting magnetically upon the switch member to rein force the bias and hold the switch member in open position when the current is relatively high butcausing the switch member to move to closed positron when the current drops to a predetermined value.

4. A circuit to be controlled, a switch con trolling the circuit, a magnetic path in which flux is set up by current in the circuit for holding the switch member from operating to rlose the switchwhen the current is high, but permitting the switch member to close the switch when the current is low, and a magnetic path in which flux is set up by current in the circuit for closing the switch.

5. A circuit to be controlled, a switch including a switch member controlling the circuit, a magnetic path in which flux is set up by current in the circuit to hold the switch member from operating to close the switch when the current is relatively high, and a magnetic path in which flux is set up by current in the circuit to close the switch when the current is relatively low and to hold the switch member closed.

6. A circuit to be controlled, a switch including a switch member controlling the circuit, a magnetic path in which flux is set up by current in the circuit to hold the switch member from operating to close the switch when the current is relatively high, and a magnetic path in which flux is setup by current in the circuit to close the switch when the current is relatively low and to hold the switch member closed, said fluxes varying at different rates as the current in the said circuit varies. A i a, i

7. A switch, a magnetic structure,,mecns for magnetizing the same, and means where by, when a portion of the magnetic structure is magnetized beyond a certain value, the switch is prevented from closing and'when magnetized at a lower value the switch is magnetically closed.

8. A switch, a magnetic structure [or closing the switch, having a portion of limited magnetic capacity, means for magnetizing the same, and means preventing the switch from closing when the said capacity is ex? cceded.

9. In a motor starter, the combination with the armature circuit, of a resistance iiicluded therein, a switch member, electromagnetic means connected with said circuit for positively moving said switch member to short circuit said resistance and acting directly upon the switch member itself for holding said member against moving so long as the current in said circuit exceeds a predetermined amount.

10. An electromagnetic switch comprising a single energizlng Winding, a pair of contacts normally in open position and caused to be closed by the'energization of said winding, and a magnetic structure acted upon by the said windingto prevent the closure of the contacts when the-wind-- ing is energized above a predetermined value.

11. An electromagnetic switch compr'ising a movable contact and a fixed contact normally out of engagement with each other, a single magnetizing winding, a mag nctic structure which when energized above a predetermined value by said' windin causes two opposing forces to be exerted upon the movable contact, one tendin to move it into engagement with the fixed contact andthe other holding it out of engagement therewith, and means whereby the holding out force is overcome by the closing force when the energizing current falls to a relatively low value so as to cause the movable contact to move into engagement with the fixed contact and be held firmly in contact therewith by said closing force;

12. An electromagnetic switch comprising a movable switch member, an electromagnet arranged to exert two forces thereon one tending to hold the switch member in open gosition and the other tending to close it, an a magnetic member of limited magnetic carrying capacity arranged to short circuit the former magnetic force at low excitation so as to causethe latter magnetic force to prevail.

13. A controlling device for electric circuits comprising a switch member having 1' two armature'portiona an electromagnet co- 14. A controllingvdevice for electric Fcircuits comprising an electromagnet having two pole p1eces,apivoted sW-it ch member having an armature portion cooperating with each of Zsaid z pole'ipieces and normally min open position with one armature portion resting adjacent one pole piece but separat ed therefrom by an-zair gap, a magnetic member which: becomessaturated'whenthe current in said uria'gnet 'is'high arranged to fshunt said air gaposo as to cause the flux of themagnet tocross the gap and hold the switch lopen :when'the current is' high and release it lwhen the current falls to apredetermined-value so. that itwill be closed by 'theother-armature portion.

I15. An electric switch comprising an electromagnet, isw itch' contacts closable thereby, and s magnetic means :fomholding said contacts 1 in ;:dpen-circuited position duringthe :passage through-stile "magneti lot a current above a predetermined value and .for moving said contacts to closedfcircuitedposition when the current through said magnet becomes of the predetermined value.

-16. I11.. a-'switch, admagnetic circuit including a movable mechanism, and a winding for producing magnetiepulls on said mechanism at two places,'said magnetic circuit having parallel paths,,-one path includin a gap, iorflcau'smg the 'pulls to vary di erently-at the twoiplaceswhen the ampere turns, in the winding are-varied, and means, for changing at tvteen-saidpulls; v t Y 17; In a swi h, a magnetic circuit including a movable member, there being air gaps in said circuit adjacent to said movable member, an energizing winding for producing opposing magnetic pulls on said movable member one or the other of which pulls may preponderate, the pull on the movable member in the direction tending to reventthe actuation of the movable memer increasing faster than that in the other direction when the current strength inthe winding is increased.

'18, A magnetic circuit including a movable member, a gap at either end of said will the relation beinga stationaryportlon and amovable pormember', and a winding for simultaneously producing, in accordance with variations of ampere turns therein a varying magnetic pull on each end of said member, the pull on the end tendin 'to prevent'movement of the movablemem er increasing faster than the pull on the other end whenthe ampere turns 'inthe winding are increased. '19.- "A magnetic circuit includin able member, a gap at either en "of said membergand a winding for simultaneously producing, in accordance with variations of ampere turns therein, a varying magnetic pull on each end of saidmember, the pull on oneend varyin differently from the pull on the other end, and means for changing at will the "relationbetween; the pulls.

20. A'magnetic circuit, an armature mov-' able with respect to two poles-fthereof, a?

winding therefor, there being a reluctance in said circuit having a 'magnetic shunt so that an excitation in the winding of a higher I than a predetermined value prevents'movement of the armature and a lower excitation 21. In an elcctromagnct switchfan enerf gizing winding, and a magnetic'circuit 'ineluding amovable mechanism, said circuit having a portion of high reluctance shunted by-a portion of lower'reluctance so: that the movable mechanism is magnetically held 'in" one position if the currentin the winding is above a predetermined value, and? the movable mechanism is caused to 'be moved by magnetic 'force to another position when the the current becomes smaller.

22. In a magnetically "operated device, a movable mechanism, a magnetizing winding which when energized sets up =two forces with respect to said movable mechanism, one actuating force tending tomove the movable mechanism, and the other an opposing force tending to prevent the same, the opposing force decreasing more rapidly than the actuating force asthe ampere turns in the winding; decreasei i 23. In a switch, a magnetic circuit includtion, switch contacts controlled-by the said movable portion, there being air-gaps at two places between saidstationary portion and said movable portion, one of said air gaps being shunted by a shunting member of magnetic material, said shunting member being of less cross section than the average cross-section of said magnetic circuit, and means for setting up a magnetic flux in said circuit.

24. In a switch, a magnetic circuit including a stationary portion and a movable portion, awinding for producing magnetic pulls on said movable-portion at two places,

the magnetic flux set up by said winding passin from the stationary portion to the mqvabfii portion through an air gap to produce a pull atone of said places and passing through an air gap and a restricted part 1')f the magnetic circuit in parallel relation thereto to produce a magnetic pull at the second of,said places, whereby the magnetic pulls on said movable portion of the mag netic circuit at said two places are caused ,to vary diiierently'wl en the ampere turns in the winding arewaried,-the winding being in series witlntheicontacts when closed.

525.,- In a swltch,'amagnetic circuit including a stationary portion and a movable porv ation, a winding zfor producing magnetic pulls on said movableportion at'two places, the-magnetic-fiux set up by said winding pass from the stationary portion to the movl l l fiei'portionithrough an air gap to pro- -duceraipull at one of saidplacesiand passing through anza-irfigap and larestricte'd part of the anagnctic cirodit. in, parallel relation thereto-to produce iamagnetic pull at the second ofsai'dplaces; whereby the magnetic wpulls on said-movable 'portiou of the magnetic circuit at said two places are caused to-vary :difi'er'ontly when the ampere turns inthe'windingmare varied, and means for 3 changing at will'th relation between the -spi'lllszatsaid two places.

-26. In1a switch,-a magnetic circuit including axstati'onary portion and a movable portion, :a' winding 'for producing magnetic pulls on said movable portion at two places, =;.-gthe'magnetic flux set up by said winding passiugirom the-stationary portion to the movable portion through an air gap to produce aipiill ht oneof said places and passing 40 throughout air' gap and a restricted part of ---=;themagnetic circuit in parallel relation thereto to-produ'cea magnetic pull at the seoond of said places, whereby the magnetic pulls on said 'movaibleportion: of the magnetic circuit at said two places are caused i:l rte-vary differently when the ampere turns in 'the windin are varied, andmeans for adjusting the air gaps at the two places relative to each other. 27.- In a switch, amagnetic circuit having movable'and stationary portions, two places on said movable portion adapted to be attracted toward said stationary portion. a winding which when energized at one value causes the attractionat one place to hold ;the said switch in the position it assumes when the winding is denergized. and means includinga magnetic shunt for causing said windin when the ampere turns therein are reduced to cause the attraction at the other -place to move the movable portion to its operated position.

28. A magnetic circuit including a movable niember,'said circuit containing an op- 1 ,supeo crating gap and a lookout gap, the operatmg gap being greatest when the movable member is in its normal unoperated position, a magnetic shunt for lockout gap, and a winding, which when energized at a oer- J tain value causes the movable memberto remain in its unoperated position, and when the ampere turns in said winding are re-e duccd causes the closure of the operatingv gap and the operation of the switch. a

29. In a switch, a magnetic circuit having an operating gap normally open and flrlOCkout gap which increases-when the operatinggap decreases, a winding foroperating said switch, and means including a magnetic shunt around the lockout gap which causes the winding --to hold the switchin its unopcrated position when energized with a car Lain number of ampere turns, and causes. the winding to close the operating gap and i operate the switch when the ampere turns are reduced. I v

30. In an electromagnetic device, a movable element, a winding formoving said element from itsinitial position, and a magnetic structure acted upon by said winding '90 to prevent the movement of said element from said initial position when'the winding is energized above a. predetermined value.

81. In a switch, a.m0vable element, an i t operating winding therefor, a pair of oontacts connected in the circuit of said winding and closable by said movable elemenhand a; magnetic structure acted upon: by said wind ing to prevent the operation of-said element when the winding isenergized above a certain value. i

32. A controlling device for electric circuits comprising a'switcli member, an electromagnct for moving said 'member to closed position, and a magnetic shuntarran ed'to cause the flux of said magnet to he the switch open when the current in the magnet is high and release itwhen the current falls to a predetermined value.

33 A controlling device for electric circuits comprising aswitch membenan electromagnct for movin said member to closed position, a magnetic s unt arrang'ed to cause the flux of said magnet to hold-the switch open when the current is high-until it falls to a redetermined value, and means for causing the magnet to hold the switch'from closing when the current asses through said predetermined value in rising to the higher value. "120 34. A controlling device for electric circuits comprising a movable switch mem'ber normally in open position having two arma ture portions, an electromagnet cooperating with one of said portions to close the switch, 125 said second armature portion resting normally adjacent 'a pole piece of said magnet but separated therefrom by an air gap, and

a magnetic member arranged to shunt said air .gap to cause second armature portion to be held upon a ruslrofcurrent above a predetermined valueand to be released when the current falls to said value.

35. A controlling device for electric circuits comprising a switch operating member having two; armature portions, an electromagnet cooperating with one of said armature portions toiclose the switch and with the other armature.portion to hold it open, and means whereby the flux of said magnet is caused to attract one armature portion when thecurrent in the magnet is relatively high andcwhen. the current falls to a predetermined value. release it and cause, it to belclosed by the other, armature portion.

36. Inna magnetically-operated. device, a magneticcircuitzhaving a plurality of arms, an energizing winding surrounding one arm ofasaid circuit, saidrarm being composed ofrthreemembers, one Ofr'Wl'llCh is movable and located between the other two, the magnetie fluxiine said movable member tending toimove-it toward ionefixed member'or the other depending- .upon the ampere turns in said winding. .37. 111a magnetically-operated device, a ma netic circuit divided into two branches of difi erent ,reluctance,-a movable member in w the circuit and an energizing winding for said circuit surrounding said movable member wherethe magnetic circuitdivides.

, 38. iIniaswitch, a branched magnetic circuit having two gaps, an energizing winding therefor, and a'movable mechanism' a portion-of'which carries the entire flux, and another portion only apart thereof, the movementfof'the movable mechanism increasing one gap and decreasing the other,

' and the second portion carrying substantially all theflux at one value of current in the energizin winding.

39; In a switc ,a magnetic circuit having a stationary portion and a movable mecha- 1 nism, switch contacts caused to close by the said mechanism, a magnetizing winding for .said magnetic circuit, substantially all' of the magnetic flux set up'in said stationary portion of said magnetic circuit by said I, magnetizing winding entering said movable mechanism throng a gap, :1 portion of the magnetic flux in said movable mechanism leaving said movable mechanism through a second gap, there being a magnetic path or shunt around the second gap.

a 40; In a switch, a magnetic circuit having a stationary portion and a movable mechanism, a magnetizing winding for said magnctic circuit, substantially all of the magin said stationary portion ofsaid magnetic circuit by the magnetizing winding entering the -movable mechanism through a gap, a portion of the magnetic tracted branch 'to cause magnetic flllx-pr0- duced by a high excitation of the windin to pass through, the gap, the force produced thereby tending to prevent the movement of the said mechanism. 4

rounding said core, a return magnetic circult external to said winding, an air gap between one end of said (ore and a part of said return magnetic circuit, a portion of the other end of the core being reduced in crosssection and'forming alshoulder with the body of the core, said reduced part of the core extending into a part of the return magnetic circuit and being surrounded by a sleeve of magnetic material, one end of said sleeve being adjustable toward or away from the shoulder on said core.

43. In a switch, a movable core adapted to actuate said switch, a'magnetizingwinding surrounding said core, a return magnetic circuit for said winding, an air gap between one part of said core and a part of said return magnetic circuit, a portionof the core toward its other end being of less crosssection than the body of the core and .extending into a portion of said return mag netic circuit, and a sleeve of. magnetic material surrounding the portion of the core of reduced cross-section, said sleeve being adjustable in a direction parallel to the axis of said core.

44. A controlling device for electric circuits comprising a movable switch member, an elcctromagnetcooperating therewith to either close the switch .or hold it open, said magnet being provided with a permanent metallic path for its flux which becomes saturated when the current in the magnet is relatively high and causes the flux to take a path which holds the switch open and when the current falls to a predeterminedvalue 42. In a switch, a movable core for actuatmg said switch, a magnetizing winding sun llt ' tween them when energized.

members, an actuating coil and means rendered effective for closing the switch only when the actuating coil is supplied with cur rent within predetermined limits.

47. An electromagnetic switch comprising a movable switch member, an electromag' net arranged to exert two forces thereon, one tending to hold the switch member in open position and the other tending to move it to closed position, and means for causing the former force to prevail at high excitation and'the latter at low excitation.

48. A controlling device for electric circuits comprising a movable switch member, an electromagnet cooperating therewith to either close the switch or hold it open, said magnet being provided with a permanent metallic path for its flux which becomes saturated upon a rush of current above a predetermined value and causes the flux to take a path which holds the switch open an d releases theswitch so that it will be closed by the magnet when the current falls to said value, and means for preventing the magnet from releasing the switch member when the current passes through the predetermined value in rising to the higher value:

49. A controlling device for electric circuits comprising a switch member, an elec tromagnet for operating the same comprising a magnetizing winding and a branched magnetic circuit cooperating therewith, and means for varying the rate 'of change of flux in said branches as the current in said winding varies.

50. A controlling device or electric circuits comprising a switch member biased" to open (position, an energizing winding arrange toexert two forces thereon one of which reinforces the bias suflicieirtly to prevent the Switch from closing when the ener izing current is relatively high while the ot ier force overcomes thebias when the energizin current is lower.

51. n electromagnet comprising a stationary core member and a movable core member having a normal flux path that tends to reduce relative movement between them an a leakage or abnormal flux path that tends 'to prevent relative movement be- 52. A magnet switch comprising a stationary core member, a coil therefor and a movable core member providing normal and leakage fluz'patlis of unequal reluctance. the ma netic flux traversing the normal, flux pat tending to produce a relative movement between the core members and the magnetic flux traversing the leakage flux path opposing relative movement of the members.

53. An electromagnet comprising stationary members and a relatively movable magnetizable core-member and .an energizing coil, the directional tendency of movement of the movable member being dependent upon the intensity of the flux produced by the coil in the said members.

54-. The combination of a circuit to be controlled, and a series of electromagnetic switches therefor, adapted to operate in a predetermined order, the operating coil of each of certain switches being brought-into the said circuit by the closure of a preceding switch and delaying the operation of the switch which it controls.

55. The combination of a circuit to be controlled, and a series of electromagnetic switches therefor, adapted to operate in a predetermined order, the operating coil of each of certain switches being brought into the said circuit by the closure of a preceding switch and holding open and later closing the switch it controls.

56. The combination of a circuit to be con-' the said circuit by the closure of a preceding switch and delaying the operation of the switch which it controls when the current in the circuit is above a certain value.

58. The combination of a circuit to be controlled, a series of electromagnetic switches therefor, adapted to operate in a fpredetermined -order, the operating coil o each of certain switches bein 'normally denergized and brought into said circuit "by the closure of a preceding switch and delaying the operation of the switch which it controls, and connections for including each coil in series with the switch it controls when it operates.

59. The combination of a circuit to be controlled, a series of electromagnetic switches therefor, adapted to operate in a predetermined order, the operating'coil of each of certain switches being brought into the said circuit by the closure of a preceding switch and delaying the operation of the switch which it controls and connections wherebg,

after all the switches have been operate only the final switch in the series is held in its operated position.

60. The combination of a motor, a circuit therefor, resistance in the circuit, a series of electromagnetic switches for controlling the resistance, adapted to operate in a predetermined order, the operating coil of each of certain switches being brought into the said circuit by the closure of a preceding switch and delaying the operation of the switch which it controls and later holding it closed.

61. The combination of an electric motor, u circuit therefor, banks of resistance in the circuit for controlling, the motor, and a series of electromagnetic switches adapted to epceding switch and delaying the switch which Signed at Cleveland, Ohio,

Fehruztry 1920.

the operation of it controls.

this lth day of ABBY R. CANFlELD. 

